There is a pretty nice "How it Works" video on steam turbines. As Pete mentions they use valving to control the speed of the turbines, interesting how they reheat the steam for the high/medium/low stages.
https://youtu.be/SPg7hOxFItI
-=Bryan=-
________________________________
From: time-nuts <time-nuts-bounces at febo.com> on behalf of Peter Reilley <preilley_454 at comcast.net>
Sent: April 5, 2017 9:34 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Line Frequeny Stablity
The response time in a large plant is very slow. Large steam plants
running at steady
state are running with their steam valves wide open. A partially
closed valve is an energy
loss and is only used when changes occur.
The power control for a plant running at a steady load is the amount of
fuel thrown into
the boiler. When you want more power you shoot more gas, oil, or coal
into the boiler.
For a nuke you pull the control rods. Behind all of this is a lot of
thermal mass. Things
don't change quickly.
Pete.
On 4/5/2017 9:01 AM, jimlux wrote:
> On 4/4/17 2:28 PM, Thomas D. Erb wrote:
>> Thanks for the info.
>>>>>> So that tells me how data is recorded - but not how the frequency is
>> kept stable ?
>>>> Is the line frequency now directly tied to GPS clock - with no drift ?
>> The line frequency is adjusted, for the most part, by adjusting the
> prime power (steam valves, dam penstocks, etc.) on the generators at
> power stations. That changes the speed, slightly, although as
> generator 1 of N starts to get ahead, the electrical load increases,
> and it slows down.
>> It's actually a pretty complex system, since there are a whole raft of
> "spring constants" in between the multiple generators in a system,
> there's phase shifts due to transmission line inductance and capacitance.
>> "Stabilizing" a system in the face of changing demand is a non-trivial
> task.
>>>>>>>>> Thomas D. Erb
>>tde at electrictime.com<mailto:tde at electrictime.com> /
>> Electric Time Company, Inc.
>> Office: 508-359-4396 x 117 / Fax: 508-359-4482
>> 97 West Street Medfield, MA 02052 USA
>> www.electrictime.com<http://www.electrictime.com<http://www.electrictime.com<http://www.electrictime.com>>
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